Firearm bolt-slide arm assembly



Nov. 17, 1964 H. A. INTO FIREARM BOLT-SLIDE ARM ASSEMBLY 2 Sheets-Sheet 1 Filed Sept. 24, 1963 INVENTOR. HENRY ,4. /N 7' O A 7' TOR/VE V Nov. 17, 1964 H. A. INT0 FIREARM BOLT-SLIDE ARM ASSEMBLY 2 Sheets-Sheet 2 Filed Sept. 24, 1963 INVENTOR HENRY A. /N 7'0 may ATTORNEY United States Patent Oftice 3,i,993 Patented Nov. it?, i954 33156393 FIREARM BOLT-SLIDE ARM ASSEMBLY Henry A. into, Wallingford, Conn., assignor to Olin Mathiesnn Chemical Corporation, a corporation of Virginia Fiied Sept. 24, 1963, Ser. No. 311,101 7 Claims. (Cl. 42-17) This invention relates to breech loading firearms and relates in particular to firearms characterized by a tubular magazine mounted below a barrel with a firing pin and breech block assembly slidably mounted for reciprocation within a receiver and in line with the barrel.

Ordinarily the breech block is actuated by a forearm as in a slide action or pump gun or by a gas or recoil device as in a semi-automatic gun.

One feature of this invention is the provision of a iirearm action having a minimum number of parts characterized by interchangeability to facilitate shifting from model to model in the course of manufacture; one novel part accomplishing as many functions as possible while uniting all parts of a given action cooperatively.

Another feature of the invention is the provision of gun parts facilitating assembly and disassembly with great ease and economy because of simplicity of structure and arrangement while improving strength and functioning of the gun.

Another feature is the provision of a smoothly functioning assembly of parts resistant to shock and wear.

A firearm embracing certain features of the present invention may comprise a receiver, trigger assembly including guide rails connected to the receiver, a pair of slide arms mounted for reciprocal motion with the receiver and operable to move along the guide rails of the trigger assembly, a breech bolt assembly including a firing pin, a bolt slide, and a bridge plate connecting the slide arms, said bridge plate releasably nesting within the bolt slide for effecting a separable connection between the breech bolt assembly and the slide arms, said bridge plate being further formed with a tail or tongue engageable with the firing pin for retaining the iiring pin within the breech bolt assembly and for limiting the motion of the firing pin.

Other features and advantages of the present invention will become more apparent from an examination of the succeeding specification and claims when read in conjunction with the appended drawings in which:

FIG. 1 is an elevational view partly in section taken on a longitudinal axis of a portion of a iirearrn incorporating the invention as viewed from the right side with sections broken away to show the action in the closed position (solid lines) and in the open position (dotted lines);

FIG. 2 is a right side fragmentary, elevational view showinfT the carrier in cartridge feeding position;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2 with some parts omitted for clarity;

FIG. 4 is an exploded perspective view from below showing in detail the structural and functional relationship between the breech bolt, the bolt slide, the firing pin, `the bridge plate and the slide arms;

FIG. 5 is a perspective view showing a modification of the bridge plate shown in FIG. 4.

The firearm shown in FIG. l includes a receiver l secured to a butt stock B, a barrel 2 is detachably connected at receiver opening 3 by means of a barrel extension 4 in accordance with copending patent application SN. 282,988, iiled May 24, 1963. The particular barrel connection utilized is not critical to the present invention.

A tubular magazine 5 is mounted on the front 6 of the receiver below the barrel to accommodate a plurality of cartridges such as the cartridge 7. A cartridge follower and spring (not shown) urge the cartridges rearwardly toward the receiver in well known fashion.

In the slide action firearmv shown, a forearm 11 is slidably mounted on the tubular magazine 5 for reciprocation. Connected in parallelism to this forearm and reciprocating therewith are a pair of slide arms l2 and i3 provided with wedge cams ld and l5, respectively, for actuating a pair of resilient cutoffs; only the left hand cutoif i6 is shown with its cam follower 17 engageable with cam l5 for movement to the left in accordance with the structure and functions disclosed in copending patent application SN. 240,586, filed November `28, 1962.

The receiver l is of inverted U-shaped construction such that a chamber or internal region lil of the receiver is bounded by spaced parallel side Walls 2l and 22 (see PEG. 3) which are substantially smooth except for a suitably positioned recess 23 at the front of the left hand wall 2l and an opposing similar recess 24 in the right hand wall 22 for accommodating the outward lateral movement of the cutotfs. At the upper right hand forward portion of the receiver is lateral cartridge port 25.

The front end 6 of the receiver has the aforementioned barrel opening 3; below opening 3 there is a front wall iii@ formed with spaced guide slots 8 and 9 for accommodation of slide arms l2 and 13, respectively.

Fixedly connected in the lower part of the receiver in conjunction with the wall and projecting to the rear therefrom is a bushing 26 supporting magazine tube 5. The bushing 26 also provides supports 13 and i9 for slide arm support bars or guide rails 4 and 49 according to copending patent application SN. 269,516, iiled April 1, 1963. t

The rear wall 20 of the receiver is provided in the longitudinal medial plane with the usual screw threaded connection le@ with the butt stock B, firing pin head recess 27, and, on the left side, a clearance opening 28 for accommodating the rear extension 29 of the left hand slide arm 13 (see FIGS. l and 4).

The upper side of the receiver is substantially closed to provide an arcuate upper wall 30 carrying a depending rib itl extending substantially the full length of the chamber medially between the side walls, preferably with a uniform downwardly converging taper along its length.

Along its underside, the receiver is formed with a large opening il providing (l) a magazine feed port in the front part of the opening including space within which the cartridge transfer mechanism operates in well known fashion, and, (2) accommodation for a trigger guard plate 5l.

Mounted in the upper part of the receiver chamber and of a shape generally complementary to the inside of this part of the receiver is breech bolt slide 31 with generally smooth parallel sides and having on its top side a longitudinally extending groove 32 with tapering sides for slidable centering and guiding engagement with the receiver rib d@ which serves to maintain antifriction clearance between the slide and receiver sides 21 and 22 without excessive side-to-side play and any misalignment.

Rib di) also serves to strengthen the top wall of the receiver.

Bolt slide 3i carries bolt 33, the front end of which is provided with an extractor 34 and a suitable number of male locking lugs 35 for releasable engagement with mating female lugs inside the barrel extension 4.

The bolt is biased forwardly with respect to bolt slide 3l and is mounted therein both slidably and rotatably Vto be moved into locking and unlocking positions by the bolt cam pin 36 operating as a follower in the cam slot 37 formed in the recessed underside of the vslide as it is moved to and fro by the slide `arms l2 and 13.`

lis thus maintained.

. Carried in a central bore of the bolt is tiring pin 38 and the firing pin spring 39 urging the pin rearwardly. The rear end of the pin is exposed to be struck, as shown in FIG. 1, upon actuation of the trigger 42 by hammer 43 biased by cooking spring 44 and carried on hammer support shaftr 45 in turn supported pivotally in bars 48 and 49.

Between the bolt slide and the slide arms is mounted a bridge element or bridge plate 60 of nearly ilat and rather simple construction, providing;

, (a) an improved connection between the slide arms and the bolt slide effecting a at surface adjacent the receiver sidewalls,

(b) connecting means and accurate spacing between the rear end of the slide arms and the bolt slide,

(c) actuating means for the cartridge transfer or carrier mechanism,

(d) an anti-friction surface for cooking the hammer,

(e) means for retaining and limiting the motion of the tiring pin,

(f) a cover plate for the bottom of the bolt slide,

g) means for connecting a cocking handle to the bolt slide.

Bridge plate 60 is recessed in the underside of slide 31 and is retained by abutments 61 and 62. The slide 31 is slotted at the bottom rear to form a ramp 63 for receptionof not only the mating ramp 65 of the plate but also of the upturned bridge plate tail or tongue 64 formed at the trailing extremity of a mating ramp 65 of the plate. The optimum elevational angle of ramp 65 is between `about 3 and 4 with the horizontal. Ramp 65 provides the hammer 43 with a low friction cocking surface as the bolt is moved back to the open position shown in FIG. 2. Ramp 65 with the aforementioned anti-frictionsurface provides not only improved cocking of the hammer 43 but also a forward component of force assisting the breech bolt assembly in its forward excursion from the open position.

Tongue 64 extends up into an annular grove 79 formed between the ring pin head and an external ring pin flange 66 for retention of the pin 38 in opposition to spring 39 bearing on the flange 66.

For operative connection with and between the slide arms 12 and 13, (a) the bridge plate 60 has on its sides laterally extending-lugs and notches, preferably with the stressrelieving llets shown at the inside notch corners,'

and, (b) the slide arms 12 and 13 have corresponding verticalnotches andlugs mating with those of plate 60. On the left side, bridge plate lugs 71 and 73 extend into notches 67 and 69 of arm 13. Similarly, right hand lugs 72 andk 74 extend into notches 68 and 7 0.

In some embodiments of the present invention, it may be desirable and economical to fabricate the bridge plate 60E andthe slide arms 12 and 13 in one unitary, integral piece part.

As the'slide arms 12 and 13 are moved forwardly, lugs 81 and 82 pushforwardly on plate lugs 72 and 71, respectively, while the shoulders of lugs 83 and 84, extending upwardly into bridge plate notches 75 and 76, respectively, correspondingly abut plate lugs 74 and 73 to drive bridge plate 60 in cooperation with a front abutment 61 of they slide 31. Y

As the slide arms are moved rearwardly, the rear shoulder of lugs 83 and 84 push on plate lugs 72 and 71, respectively, while shoulders 85 and 86 correspondingly abut plate lugs 74 and 73 in cooperation with an abut.

a motion by the slide at abutments 61 and 62 and by plate 60'and against outward motion by the receiver sidewalls 21 and 22`(see FIG. 3). Proper spacing of the slide arms For actuating the carrier, plate 60 has a window 90 4 89. The window includes slot 92 providing clearance for tray tab 55 (see FIGS. 1 and 4).

For converting to a semiautomatic type 0f repeating firearm, there is provided a modified bridge plate 60B (FIG. 5) having features generally (corresponding structure has heen identied by addingletter B to reference numerals) identical with those of plate 60 except for provision of a cooking handle 103 formed integrally with plate 6GB. The cooking handle is connected and bent upwardly at'a stress relieving hole 181. To t plate 60B, bolt slide 31 has a cutaway 182 (FIG. 4) for reception of handle 103.

It is understood that the separate arrangement of the bridge plate 60 and slide arms 12 and 13, as shown, is preferred for interchangeability and ease of assembly but these members may be made integrally from sheet metal stock if desired.

By referring to FIG. 3, it is apparent that the present invention provides a neat, clean, narrow stack of piece parts withinl the smooth interior sidewalls 21 and 22 of the receiver in that guide rails 48 and 49 support slide arms 12 and 13 while the slide arms neatly intermesh with bridge plate-6i) in turn nested into the underside of bolt slide 31.

Note that the sides of bolt slide 31 adjacent the receiver sidewalls 21 and 22 define a smooth plane surface which includes the side edges of the bridge plate 60, the flat sides of the slide arms 12 and 13 and the at sides of the guide rails 48 and 49. v

As stated previously, supporting bars o-r guide rails 48 and 49 are received at their front ends in laterally xed spaced relationship in sockets 18 and 19 of the receiver while their rear ends are fastened to the receiver by cross pin 95.

One transverse stud 96 pivotally supports carrier 54 upon the rails 48 and 49. The carrier 54 is shown in FIG. 1 in downward position ready for accepting a cartridge from the magazine and poised for tilting upwardly to transfer the cartridge into the chamber in well known fashion.

The shell 7, released from the magazine under control of the cutoifs, is lifted in front of the breech bolt by the action of the carrier 54 in moving from the position shown in FIG; 1 to the position shown in FIG. 2.

When the forearm 11 and slide arms 12 and 13 are retracted to put the bolt slide 31 in the open position as at 31A (dotted line position in FIG. 1), the bridge plate 60 overrides the upper edge 52 of pawl 89 turning it back to the position indicated at 52A. At this time notch SiS-engages bridge plate window 90 at edge 91 as shown in dotted lines. During forward motion of the bolt slide 31 and bridge plate 6), the carrier pawl 89 and rear end 53 of the carrier 54 are pushed downwardly causing the frontend of the carrier to lift cartridge 7 upwardlyV asl shown in FIG. 2 in well known fashion. At the same time, the pawl rotates sufficiently to pull the notch 88 out of positive engagement ,with window 90 permitting the bridge plate to slide over the pawl and the'bolt 33 proceeds to chamber the cartridge.

It is anticipated that a variety of modifications may Y be devised without departing from the spirit and scope of the present invention. What is claimed isi v 1. In combination, in a firearm, a bolt assembly, a cartridge carrier 1neansa pair of slide arms forractuating and reciprocating said bolt assembly, said assembly comprising a bolt slide, a bolt movably disposed inV said bolt slide, "a tiring pinrpositioned in thebolt including spring means tending to drive the firing pin out of the bolt,

said bolt slide being formed'with a recess and a notchY defining a rst ramp, a bridge plate disposed in said recess, said bridge plate being formed with aV mating second ramp and a ltongue soathat when the bridge plate is disposedwithin the bolt slide'` the tonguel is operable to engage and to retain the ring pin and the mating ramps nest with one another, said bolt slide and said Slide arms being formed with cooperating lugs and notches effective to make a releasable connection between the bolt slide and the slide arms through the instrumentalit of said bridge plate.

2. ln a firearm having a breech bolt-slide arm assembly, the improvement comprising a bolt slide for movably supporting the bolt, a pair of spaced slide arms for driving said bolt slide, said slide arms being formed with lugs and notches, cam means formed in the bolt and bolt slide operative to move the bolt relative to the bolt slide axially and rotationally, said bolt slide having a relatively open face exposing the cam means to the atmosphere, said bolt slide being formed in the region of said open face with a generally rectangular recess, a bridge plate complementary to said recess disposed in the recess operative to substantially close said open face, said bridge plate being formed with opposed lugs and notches complementary to said lugs and notches formed on said slide arms operative to make a driving connection between the bolt slide, the slide arms, the side Walls of said bolt slide, the side edges of the bridge plate creating a vertical stack so as to define two, spaced, generally parallel plane surfaces.

3. A breech bolt slide arm assembly in accordance with claim 2 above wherein the bridge plate is formed with an operating handle which interrupts or intercepts one of said plane surfaces.

4. A firearms bolt and cartridge carrier combination in accordance with claim 1 wherein the bridge plate is formed with a Window operative to engage and drive said cartridge carrier means.

5. In a rearm having a receiver, a breech bolt slide mounted and guided in said receiver for longitudinal reciprocation, laterally spaced slide arms extending longitudinally into said receiver, a bridging means separate from said slide and positioned on the underside of said breech bolt slide, said bridging member extending substantially straight across said slide between said arms,

abutment means on said breech bolt slide engaging said bridging means to prevent longitudinal relative movement between said breech bolt siide and said bridging means, cooperating means on said siide arms and said bridging means to keep said bridging means between said slide arms and connect said slide, arms, and bridging means for longitudinal reciprocation together.

6. A firearm including a receiver having internally substantially smooth and parallel, laterally spaced sidewalls extending longitudinally, a breech bolt and a firing pindriving hamm r in said receiver, and a pair of longitudinally extending slide arms extending into said receiver for actuating said bolt and cooking said hammer, a bolt slide housed in said receiver and guided for longitudinal reciprocation with said bolt movably coupled to said slide, a tiring pin movably retained in the bolt together with resilient means for rearwardly biasing said pin with respent to said bolt, said slide being formed with a laterally extending recess and a notch, and a detachable bridging means shaped to be releasably received in said recess, said bridging means being a generally planar member formed with a longitudinally extending ramp and a tongue disposed in said notch to engage and to releasably retain the biased tiring pin, said ramp being directed at an elevational angle to slidably engage said hammer, said bridging means and said slide arms being formed and assembled together to longitudinally guide not only said arms laterally spaced between said sidewalls but also said bridging means between said arms and to releasably connect said bridging means and the slide arms for reciprocating said slide through the instrumentality of said bridging means.

7. The firearm of claim 6 including cartridge carrier means and an edge on the bridging means, said edge being operative to engage and drive said cartridge carrier means.

References Cited in the le of this patent UNITED STATES PATENTS 3,075,313 Allyn Ian. 29, 1963 

1. IN COMBINATION, IN A FIREARM, A BOLT ASSEMBLY, A CARTRIDGE CARRIER MEANS, A PAIR OF SLIDE ARMS FOR ACTUATING AND RECIPROCATING SAID BOLT ASSEMBLY, SAID ASSEMBLY COMPRISING A BOLT SLIDE, A BOLT MOVABLY DISPOSED IN SAID BOLT SLIDE, A FIRING PIN POSITIONED IN THE BOLT INCLUDING SPRING MEANS TENDING TO DRIVE THE FIRING PIN OUT OF THE BOLT, SAID BOLT SLIDE BEING FORMED WITH A RECESS AND A NOTCH DEFINING A FIRST RAMP, A BRIDGE PLATE DISPOSED IN SAID RECESS, SAID BRIDGE PLATE BEING FORMED WITH A MATING SECOND RAMP AND A TONGUE SO THAT WHEN THE BRIDGE PLATE IS DISPOSED WITHIN THE BOLT SLIDE THE TONGUE IS OPERABLE TO ENGAGE AND TO RETAIN THE FIRING PIN AND THE MATING RAMPS NEST WITH ONE ANOTHER, SAID BOLT SLIDE AND SAID SLIDE ARMS BEING FORMED WITH COOPERATING LUGS AND NOTCHES EFFECTIVE TO MAKE A RELEASABLE CONNECTION BETWEEN THE BOLT SLIDE AND THE SLIDE ARMS THROUGH THE INSTRUMENTALITY OF SAID BRIDGE PLATE. 